Knowledge that Transforms

This paper studies how new varieties enter markets and become locally available. We provide causal evidence of demand externalities that operate in two steps. First, information about new varieties diffuses directly through real-world social ties among consumers. Second, early purchases generate an indirect spillover to firms: local retailers learn from “pioneer” consumers which new varieties are most likely to succeed and adjust their product offerings accordingly. We study this process in the context of direct-to-consumer imports. Using customs records on individuals’ purchases matched to population-wide social networks, international migrant links, and retailer catchment areas, we document economically meaningful demand externalities. Product-specific expenditure shocks abroad transmit through migrant networks and shift which varieties consumers purchase. Leveraging these shocks as a plausibly exogenous source of local demand variation, we show strong peer effects: prior purchases by close neighbors, coworkers, or friends increase an individual’s likelihood of purchasing the same variety, especially for premium and visible goods. We leverage this result to identify an indirect spillover from consumers to firms: retailers are more likely to add a variety to their assortment when it becomes popular among consumers in their catchment area. Combining the instrument with linked consumer–retailer data and a self-conducted retailer survey, we show that this response reflects learning about latent demand for varieties not yet stocked locally. Together, social diffusion and retailer learning generate demand multipliers that reshape local product availability and expand access to global variety.

The US trade war against China can either enhance or diminish American soft power in China, depending on whether Chinese citizens view it as legitimate. We study how US movie viewership, a measure of American soft power, responds to the trade war. We find a significantly greater reduction in US movie viewership in regions more exposed to the Trump tariffs, but no corresponding decline in non-US movies. The decline is stronger for action and drama movies, which tend to embody greater perceived “Americanness.” Survey data also show a sharper decline in trust in Americans in more tariff-exposed regions.

We study how contracting and monitoring structures in public procurement affect large-scale infrastructure construction. Starting in 2016, Kenya’s public electric utility ran competitive auctions and then awarded and administered dozens of procurement contracts to connect millions to electricity. The causal analyses leverage natural and experimental variation and granular, independentlycollected construction quality data. Kenya Power contracts funded by the World Bank featured unbundled contract components known as ‘design-bid-build’ and enhanced monitoring compared to African Development Bank-funded contracts. Unbundling contracts delayed construction progress but improved quality. Randomized inspections improved quality without large delays. Bundled contracting with additional independent monitoring could improve outcomes.

We study how tax incentives affect the return migration of high-skilled expatriates to their home country, exploiting a generous income tax break for returnees in Italy. Using administrative data and a Triple-Difference design, we estimate a migration elasticity to the average net-of-tax rate just below one. Responses are sizable across the upper half of the earnings distribution, indicating that tax-induced migration is not limited to top earners. A cost-benefit analysis reveals that, while costly in the short term, the scheme pays for itself in present value if a sufficiently large fraction of returnees remains after the scheme elapses.

We study the real and allocative consequences of relaxing gender-specific credit constraints by analyzing a blended finance program designed to expand bank lending to female entrepreneurs in Turkey. Merging credit registry, tax, and matched employer-employee data, we find participating banks raised their credit share to women by over 18%, spanning repeat, poached, and first-time borrowers. Beneficiary firms invest more, grow employment, sales, and profits, diversify their networks, and exit less. Treated banks also expand lending to male entrepreneurs, though the increase is smaller and disproportionately directed toward higher-productivity firms, suggesting reallocation rather than crowding out. District-level effects are absent, reecting the program’s modest scale.

We examine the preferences of low-income households in Kenya over the structure of unconditional cash transfers. Most preferred lumpy transfers, and some preferred deferred receipt—in contrast to the typical structures of safety-net programs, but consistent with evidence on the financial challenges of poverty. Turning to consequences, receiving transfers later in the year raised income 1.5 years later—but willingness to defer receipt was sensitive to small changes in cash flow around the time of decision-making. Taken together, these results illustrate how adapting cash transfer design to the decision-making environment of those in poverty could improve financial choices and outcomes.

How can short episodes of localized hostility shape regional economic trajectories that even amplify over time? I exploit economic differences across the idiosyncratic and short-lived line of contact between the Red Army and the Western Allies in South Austria at the end of WWII. The 74-day hostile presence of the Red Army shaped the age- and occupation-structure via refugee flows, causing amplifying demographic effects over time and backwardness in sector development and tax revenues. My findings also point to the isolated role of the Red Army’s hostile actions after WWII in understanding the European economic East-West divide.

Information is central to consumer credit, but little is known about its equilibrium effects. We study a 2017 natural experiment in which non-bankruptcy public records were purged from U.S. credit reports. The large information-removal differences across states allow us to identify equilibrium impacts. Available credit increased for consumers who lost negative information directly. Consistent with our model, available credit declined indirectly for consumers who did not lose the negative information because they could no longer distinguish themselves. The direct and indirect effects nearly canceled, so the net equilibrium effect after a year was nearly zero but with substantial redistribution.

We assess the empirical evidence for the hypothesis that women more than men respond to changes in treatment. First, we examine whether the results of over two hundred experimental economics papers support the female sensitivity hypothesis. Second, using data from two studies (DellaVigna and Pope, 2022; Exley et al., 2025), we conduct over two hundred pairwise tests of the hypothesis. Both analyses show that gender is not predictive of responsiveness to treatment. We further examine how the hypothesis has been disseminated in the literature and find that it is referenced predominantly by papers that support it.

We examine parental response to a fetal shock using data from 150 Demographic and Health Surveys in 50 developing countries. Focusing on the impact of Ramadan fasting, a common shock experienced by more than a billion Muslims worldwide, we find that children exposed to Ramadan fasting during pregnancy have lower rates of full vaccination for DPT and polio compared to their non-exposed siblings. Further, parents tend to compensate for the fetal shock during booms and reinforce during economic downturns. Our estimations suggest that this has resulted in approximately half a million excess infant deaths over the past three decades.